This invention relates to piperazine derivatives of theophylline and theobromine and to their utility as treatment compounds for respiratory and allergic diseases.
Theophylline and theobromine are well known as diuretics, cardiac stimulants and smooth muscle relaxants. Addition of the piperazine containing substituent confers a range of pharmacologic activities which render the resulting compounds useful in the symptomatic treatment of asthma, hay fever and other respiratory diseases such as, for example, the common cold. The compounds of this invention are sulfur oxidized derivatives and N-demethylated analogs of the piperazine derivatives of theophylline and theobromine which are disclosed in U.S. Pat. Nos. 4,374,835, 4,374,837 and 4,400,381. It has been discovered that the compounds of this invention possess an unexpectedly high degree of antihistaminic activity and prolonged duration of action.